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Designing a Green, Inquiry-Based Organic Chemistry Laboratory to Educate the Next Generation of Scientists
Loyd Bastin & Kaitlyn GerhartWidener University
Teaching Green Chemistry“The era of procrastination, of half-measures, of soothing and baffling expedients, of delays is coming to its close. In its place we re entering a period of consequences.” – Winston Churchill
• We need to change the culture/mindset• We must educate students about GC in a way that encourages
application of their knowledge• Green Organic Chemistry Experience VS Green Organic Chemistry
Labs
• Involve Students in the Process• Interviewed faculty about desired techniques for students
to learn
• Searched for experiments in the Journal of Chemical Education and GEMS database
http://greenchem.uoregon.edu/gems.html• Developed a 3-step synthesis as capstone experience• Designed course to introduce Green Principles and
techniques• Students APPLY this knowledge in the final experiment
How We Designed Our Lab
Extractions Chemical/Waste HandlingChromatography Hazard AwarenessIR GC
• Introduction to Environmental Contamination & Chemical Exposure
• Introduction to Green Chemistry• Traditional vs Green Approaches• 12 Principles of Green Chemistry
• It’s important for students to apply Green Chemistry• Analyze greenness of current experiments
• Percent Yield, Atom Economy, Atom Efficiency, Effective Mass Yield, E-Factor
• Revise/design experiments
• Important to build-up as semester progresses
Creating a Green Chemistry Culture
Techniques used:• Solubility• Recrystallization• Melting point• Mixed melting point
How it’s Green:• Not explicitly green
Recrystallization & Mixed MPs
Modified from a procedures acquired from Prof. Jim Patterson, Seattle Community College.
Techniques used:• Liquid-liquid extraction• Recrystallization• Mixed solvent
recrystallization
How it’s Green:• Benign extraction
solvents
Acid/Base Extraction
Biosynthesis of EthanolIsolate/purify ethanol produced by yeast fermentation. This experiment is used to introduce Green Chemistry.
How it’s Green:
• Benign reagents
• Renewable feedstocks
• Ethanol used later
• Atom economy
Techniques used:
• Simple distillation
• Fractional distillation
• gas chromatography
Adapted from experiment by J. Thompson, Lane Community College, GEMS database, July 2006.
Friedel-Crafts Acetylation
Adapted from: Mohrig et al. Modern Projects & Experiments in Organic Chemistry: Miniscale and Standard Taper Microscale, 2nd ed. W.H. Freeman: New York: 2003, 173-176.
Techniques used:• EAS• Column
chromatography• Thin layer
chromatography• Melting point• IR spectroscopy
How it’s Green:• Greener reagents
Isolation of the Three Components of Spearmint Oil
Experiment adapted from Don R. Davies; Todd M. Johnson. J. Chem. Ed. 2007, 84, 318-320.
How it’s Green:• Greener reagents
Techniques used:• Column chromatography• Thin layer chromatography• IR spectroscopy
• Capstone experiment• Students APPLY Green
Chemistry Knowledge• Focuses on choosing
greener methods• Emphasizes
Techniques from previous experiments
Synthesis of 1,2-dibromo-1-phenylpropane
In the Classroom• Students research methods for each step • Required to bring at least one potential procedure for
each reaction to the lab lecture • Class explores different methods using Green Metrics
Techniques used:• Liquid-liquid extraction• IR spectroscopy• BP determination
How it’s Green:• Atom economy• Atom efficiency
Experiment basics:• Ethanol from biosynthesis• CH2Cl2 used for extraction• Can experiment with
greener solvents• Product verified by BP & IR
Other Reagents• Baker’s Yeast• Carrot Reduction• LiAlH4
Experiment adapted from N. Pohl et al. J. Chem. Ed. 2002, 79, 727–728.
Reduction of Propiophenone
Techniques used:• Distillation• IR spectroscopy• BP determination
How it’s Green:• Greener reagents• Atom economy• Atom efficiency
Experiment basics:• H3PO4 vs H2SO4
• Distillation purifies as well as drives rxn
• No work up necessary• Pdt verified by BP and IR
Experiment adapted from: Doxsee et al. Green Organic Chemistry. Thomson 2004. 129-134.
Elimination of 1-phenyl-1-propanol
Experiment basics:• Opportunity to work with
strong acids
Other Reagents• Pyridinium tribromide• Br2 in CH2Cl2• Br2 in Me-THF
Techniques used:• Recrystallization• IR spectroscopy
How it’s Green:• Greener reagents• Atom economy
Experiment adapted from: McKenzie et Al. J. Chem. Ed. 2005, 82, 306-310.
Bromination of trans-β-methylstyrene
Summary• Laboratory emphasizes applying green chemistry • Exposed to different chemical methods and challenged
to ‘think green’• Exposed to a wide variety of techniques• Final synthesis provides a venue for applying Green
Chemistry to a synthetic protocol• Analysis by NMR can easily be added if desired
What’s Next?• We are now having students “Green” the synthesis of
Aromatic Sulfa Drug Analogs in Organic II Lab
AcknowledgementsKaitlyn GerhartOrganic Chemistry students:
Fall 2007, 2009Summer 2008, 2009
Krishna BhatIrina Knyazeva
UO GCEWA&S Summer Housing
FellowshipWidener Faculty Development
GrantChemistry, biochemistry, and
biology faculty
“There’s nothing that unusual about what I’m doing……. What is unusual is that I had the privilege to be shown it as a young man.” – Al Gore
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